Drug interactions
Mifepristone + Posaconazole
Severity: Major
Mifepristone and Posaconazole: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Posaconazole can substantially increase mifepristone exposure, raising the risk of adverse effects such as hypokalaemia, adrenal insufficiency and QT prolongation. Both drugs can also prolong the QT interval independently.
What this interaction means in plain words
Mifepristone and Posaconazole can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Mifepristone belongs to Endocrine; Posaconazole belongs to Anti Fungals.
Why it happens
Posaconazole inhibits CYP3A4 metabolism of mifepristone, with additive QT prolongation.
What to do
Avoid the combination if possible; in Cushing syndrome, do not exceed 300 mg/day of mifepristone. Monitor ECG, potassium and signs of adrenal insufficiency.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Other interactions of Mifepristone
- Apixaban + Mifepristone Contraindicated
- Argatroban + Mifepristone Contraindicated
- Cisapride + Mifepristone Contraindicated
- Cortisone + Mifepristone Contraindicated
- Cyclosporin + Mifepristone Contraindicated
- Dabigatran etexilate + Mifepristone Contraindicated
Frequently asked questions
Can I take Mifepristone with Posaconazole?
MediHelp rates the interaction as major. Mifepristone and Posaconazole can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Posaconazole can substantially increase mifepristone exposure, raising the risk of adverse effects such as hypokalaemia, adrenal insufficiency and QT prolongation. Both drugs can also prolong the QT interval independently.
How serious is the interaction between Mifepristone and Posaconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination if possible; in Cushing syndrome, do not exceed 300 mg/day of mifepristone. Monitor ECG, potassium and signs of adrenal insufficiency.
What other medicines interact with Posaconazole?
MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.
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